Sheet coating apparatus and method of repairing said apparatus



Aug. 30, 1966 E. J. SCHUTZE SHEET COATING APPARATUS AND METHOD OF REPAIRING SAID APPARATUS Filed May 5, 1964 INVENTOR United States Patent 3,2683% SHEET (JUATRNG APPARATUS AND METHOD 6F REPATREING SAID APPARATUS Edward J. Schuitze, Mount Prospect, ilk, assignor to Nationai (Ian (Zorporation, Qhicago, 1th., a corporation of Deiaware Fiied May 5, 1954, Ser. No. 364,912 9 tCiaims. (Ci. 29-M8.4)

This invention relates to improvements in apparatus for coating sheets of material, such as tinplate or aluminum, that are to be subsequently cut into can body blanks and method of repairing said apparatus.

In a sheet coating apparatus of the type with which the present invention is concerned, the sheets of metal are fed between a coating roller and an impression or scraper roller for purposes of applying a coating of lacquer, varnish or the like onto one side of the sheet. The sheets are driven through the rollers in precise registration by the cooperative action of the two, and to prevent slippage of the sheet the rollers should rotate at substantially the same peripheral speed. The lacquer coating usually is applied in a precise pattern over discontinuous areas of the sheet leaving uncoated stripes on the sheet that will ultimately form the side and end seams of the can body. The lower or impression roller bears against the side of the sheet that will ultimately be the inside surfaces of the can bodies that are formed from the sheet, and these inside surfaces must be kept free of lacquer, especially if the cans are to be used for food products since even a small amount of lacquer on the inside surface of the can tends to alter the taste of the food product therein.

As long as the sheets are successively fed between the two rollers, the back side of the sheet (i.e. the side that faces the impression roller) does not become coated. However, for various reasons, successive feed of the sheets is interrupted and when this occurs the coating roller applies a lacquer coating to the impression roller. The lacquer would then be transferred to the back side of the next sheet that is fed between the two rollers. To prevent this from happening, one or more scrapers are pressed against the surface of the impression roller to remove any lacquer that may become deposited thereon. The surface of the impression roller may also be washed with lacquer thinner to assist in keeping it free of lacquer.

The scraper or scrapers tend to wear down the periphery of the impression roller, reducing the diameter thereof and thereby decrease its peripheral speed relative to that of the coating roller. Furthermore, the impression roller does not wear down uniformly but generally be comes scored with circumferential grooves due to the action of the scrapers as well as the abrasive action of certain pigments which tend to collect in small pools on the edge of the scraper. pression roller has become worn and scored, it is removed from the machine and its periphery is ground undersized to remove the grooves and render its surface smooth and true. When the impression roller is again replaced in the coating machine its peripheral speed will be less than the peripheral speed of the coating roller by an amount depending upon the amount of metal machined from its surface.

Since the peripheral speeds of the coating and impression rollers must be kept reasonably constant, if there is too much variation in these peripheral speeds, there is slippage between the sheet and the impression roller, causing a misregistration of the coated spots on the sheet. This results in the formation of faulty can body blanks in subsequent can making operations that slit the sheet into body blanks. Therefore, there is a limit to the Therefore, after the im-,

amount of undersize that can be permitted in the impression roller, and impression rollers which must be machined below the minimum permissible undersize to be otherwise serviceable must be discarded. For example, in a sixty sheet per minute coater it has been found that where a twelve inch diameter coating roller running at a peripheral speed of 188.4960 feet per minute is used with an eight inch diameter new impression roller having the same peripheral speed, a reduction in the outer diameter of the impression roller of .020 inch results in reduction in peripheral speed of the impression roller of about onefourth inch per minute. This difference in peripheral speeds of the two rollers is reflected in error of registration of the spots coated on the sheet, especially since the error on the sheet in travel multiplies, increasing from front to rear of the sheet.

It is, therefore, an object of the present invention to provide a sheet coating apparatus having coating and impression rollers between which the sheets are fed and wherein the drive tothe two rollers are independent and with at least one of the drives being capable of continuously variable adjustment so that the peripheral speeds of the two rollers may be rendered the same, notwithstanding that the impression roller has been machined below its original diameter.

It is a further object of the present invention to provide, in an apparatus of the type stated, a method which permits the periphery of the impression roller to be machined to an undersized diameter and then rotated at a higher number of revolutions per minute than it was rotated prior to machining to bring the peripheral speed of the impression roller up to that of the coating roller.

It is another object of the present invention to provide a method and apparatus of the type stated which permits a substantial reduction in the cost of maintenance and operation of the coating machine by prolonging the useful life of the impression roller many times over that heretofore obtainable. Where the impression roller is surface hardened and thus has a cylindrical peripheral shell that is harder than the part of the roller radially inwardly of the shell, the roller may be repeatedly machined as long as a part of the hardened shell remains.

It is an additional object of the present invention to provide a method and apparatus of the type stated which is readily adaptable to existing coating machines.

The attainment of the above and further objects of the present invention will be apparent from the following specification taken in conjunction with the accompanying drawing forming a part thereof.

In the drawing:

FIG. 1 is a longitudinal sectional View, partially in section and somewhat diagrammatic, of a sheet coating apparatus constructed in accordance with and embodying the present invention; and

FIGS. 2 and 3 are fragmentary sectional views taken along lines 22 and 33 respectively of FIG. 1.

Referring now in more detail to the drawing, 1 designates a conventional coating machine of the type employed in lacquer and varnish coating of metal sheets from which can body blanks are thereafter made. One such machine is shown and described in Wagner et a]. Patent 1,848,856. So far as concerns the present invention, such machine comprises a feed table 3 for support ing sheets 5 which are successively fed to the table in a conventional manner from a stack of such sheets (not shown). The feed table 3 has longitudinal slots 7, 9 for receiving pushers 11, 12 that engage the trailing edge of the sheet 5 and advance the sheet along the table toward the parallel cylindrical coating and impression rollers 13, 15 for passage therebetween. The pushers 11, 12 are mounted on parallel drive chains 17, 19 which are trained around a pair of sprockets 21, 23 which are, in turn, mounted on parallel shafts 25, 27. A support plate 29 underlies the feed table 3 for supporting the central part of the upper run of each chain 17, 19. Also mounted on the table 3 are one or more side guides 29, 31 which are spring biased at 33, 35 and engage the side margins of the sheet to maintain it in proper side registration immediately prior to passage of the sheet between the rollers 13, 15.

The coating roller 13 has a shaft 33 which is journalled in bearing blocks 35, 37 which are vertically adjustable in any suitable manner as by screws 39, 41. The surfacing layer 43 of the coating roller 13 may be of rubber, plastic, or the like and is contoured to provide the desired pattern of spots of lacquer coating on the sheet 5. By way of example, the surfacing layer 43 has grooves 45 so as to divide the layer into sections 47 whereby the roller 13 will apply to the sheet a pattern that has rectangular coated areas corresponding to the sections 47 and uncoated strips corresponding to the grooves 45. It will be understood, however, that the surface of the coating roller 13 may be contoured to provide other patterns, as desired.

The coating material 48, such as lacquer or varnish, may be stored in a suitable reservoir 49 and supplied to the coating roller 13 in a conventional manner, as for example, by fountain rollers 46, 51, 52.

The impression roller is mounted below the coating roller 13 and has a shaft 50 that is journalled in bearing blocks 53, 54. These blocks 53, 54 may be vertically adjusted in a conventional manner as by screws 55, 57. The roller 15 is preferably of metal and may have its outer cylindrical surface 56 hardened to a suitable depth. The edge of a conventional scraper 58 is disposed against the roller surface 56 throughout the length thereof. The scraper 58 is preferably rockable about the axis of a scraper support bar 60, and the scraper 58 may be biased into pressure engagement with the roller surface 56 by a spring 61. While one scraper 58 is herein illustrated, it will be understood that more than one scraper may be used. Any coating material 48 that may become deposited on to the roller 15 by the roller 13, as for instance when the two rollers 13, 15 rotate a revolution without a sheet passing therebetween, will be removed by the scraper 58. To further facilitate removal of the coating material 48 from the peripheral surface 56 of roller 15, a conventional spreader roller 62 may be used to distribute and thin out the applied coating on the peripheral surface 56. Also the surface 56 may be con tinuously washed in a conventional manner by lacquer thinner or other solvent for the coating material 48.

The machine 1 may be driven by an electric motor 64 that drives a shaft 65. A gear 66 drives a gear 67 on the coating roller shaft 33 through an idler gear 68. Also the chains 17, 19 may be driven from the shaft 65 through a drive belt or chain 69. The various other drives as well as other components of the machine 1 are all known in the art and are, therefore, not shown or described herein.

In the machine of the present invention the drive shaft 65 has pulleys 70, 70 around which drive belts 71, 72 are trained. These belts drive the impression roller shaft 50 through a variable speed transmission 73. This transmission may be of the split cone pulley type that is mounted or otherwise coupled to the shaft 50 to provide a continuously variable adjustment of the speed of rotation of the impression roller 15 independently of the speed of rotation of the coating roller 13. Any suitable variable speed transmission 73 may be used, for example those of the general types shown in Luenberger Patent 3,109,315; Steuer Patent 3,110,189, or Williams Patent 3,108,483, the disclosures of which are by reference incorporated herein. By adjusting the speed of rotation of the impression roller 15 relative to that of the coating roller 13, the peripheral speeds of the two rollers may be made previously the same to prevent slippage of the sheet 5 relative to the coating roller and resultant error in the registration of the coated spots on the sheet. The impression roller 15 is of smaller diameter than the coating roller 13; therefore, the impression roller must rotate at a higher number of revolutions per minute than the coating roller. Since the peripheral speed of the coating roller 13 is known for a given motor 64 speed, and the diameter of the impression roller 15 is known, the proper speed of rotation of the latter can be computed. A tachometer 75 may be attached to the shaft 50 so that the transmission 73 may be adjusted until the tachometer gives the proper r.p.m. reading for the shaft 50.

When the surface 56 of the impression roller has become worn and scored, the impression roller 15 may be removed from the machine 1 and the surface 56 ground or otherwise machined to refinish it. Thereafter, the roller 15 may be replaced in the machine and the bearing blocks 43, 54 adjusted. With the amount of undersize of the diameter of the surface 56 being known, the proper r.p.m. of the impression roller 15 may be computed which will give the impression roller the same peripheral speed as that of the coating roller 13. The transmission 73 is then adjusted to give this r.p.m. reading on the tachometer 75.

The impression roller 15 may be removed from the machine 1 and ground down several times before it must be discarded, since each time the diameter of the roller 15 is reduced, its speed may be correspondingly increased to give it the proper peripheral speed. This materially prolongs the useful life of the roller 15 and results in substantially cost savings in the operation of the machine.

When a new impression roller '15 is ultimately used to replace a previously machined roller '15, the new roller will have a greater diameter than the discarded roller. There-fore, the output speed of the transmission 73 will have to be reduced an appropriate amount.

In compliance with the requirements of the patent statutes I have herein shown and described a preferred embodiment of the invention. It is, however, to be understood that the invention is not limited to the precise con struction herein shown, the same being merely illustrative of the principles of the invention. What is considered new and sought to be secured by Letters Patent is:

1. In a sheet coating apparatus, a coating roller and an impression roller, driving means for rotating the rollers in timed relation, means for delivering a sheet to the rollers, the peripheries of said rollers cooperating to grip the sheet and feed the sheet therebetween and apply a coating of material from the coating roller to one side of the sheet, scraper means disposed against the periphery of the impression roller for removing therefrom coating material that has been deposited thereon by the coating roller and thereby prevent coating mate-rial from being deposited by the impression roller onto the other side of the sheet, and means forming part of said driving means for adjusting in a continuously variable manner the speed of rotation of one roller relative to the other to render the peripheral speeds of the two rollers substantially the same.

2. In a sheet coating apparatus, a coating roller and an impression roller, driving means for rotating the rollers about parallel axes at the same peripheral speed, means for delivering a sheet to the rollers, the peripheries of the rollers cooperating to grip the sheet and feed the sheet therebetween and apply a coating of material from the coating roller to one side of the sheet, scraper means disposed against the periphery of the impression roller for removing therefrom coating material that has been deposited thereon by the coating roller and thereby prevent coating material from being deposited by the impression roller onto the other side of the sheet, and means forming a part of said driving means for adjusting the speed of rotation of the impression roller relative to that of the coating roller so that impression rollers of various diameters maybe used with the coating roller and be rotated at substantially the same peripheral speed as that of the coating roller.

3. In a sheet coating apparatus, a coating roller having means for applying a coating of material to one side of a sheet in a predetermined pattern that leaves at least one uncoated region, an impression roller, driving means for rotating the rollers about parallel axes at the same peripheral speed, a feed table, means for advancing the sheet along the feed table to the rollers in timed relation to the rotation of the rollers, the peripheries of said rollers cooperating to .gripthe sheet and feed the sheet therebetween and apply the coating to the sheet in said predetermined pattern, scraper means in pressure engagement against the periphery of the impression cylinder for removing therefrom coating material that has been deposited thereon by the coating roller and thereby prevent coating material from being deposited by the impression roller onto the other side of the sheet, and transmission means forming part of said driving means for adjusting in a continuously variable manner the speed of rotation of the one roller relative to the speed of rotation of the other roller so that impression rollers of various diameters may be used with the coating roller and be rotated at substantially the same peripheral speed as that of the coating roller.

4. In a method of repairing a sheet coating apparatus having a coating roller, an impression roller rotatable at the same peripheral speed as and cooperating with the coating roller to grip and feed a sheet therebetween to apply a coating of material from the coating roller to one side of the sheet, and scraper means in pressure engagement with the periphery of the impression roller for removing therefrom coating material that may become deposited thereon and wherein the scraper causes irregular wear of said periphery; the steps comprising machining the periphery of the impression roller to reduce the diameter thereof, and thereafter changing the speed of rotation of the one of the rollers relative to that of the other roller suflicient to render the peripheral speed of the impression roller substantially the same as that of the coating roller.

5. In a method of repairing a sheet coating apparatus having a coating roller and an impression roller both rotatable at the same peripheral speed, and wherein the use of the apparatus causes roughening and irregular wear of said periphery; the steps comprising removing the impression roller from the apparatus, removing sufiicient material from the periphery of the impression roller to eliminate the roughened and irregularly worn surface, replacing the impression roller in the apparatus such that its periphery is at least as close to that of the coating roller as before removal of the impression roller and thereafter changing the speed of rotation of one roller an amount sufficient to render the peripheral speed thereof substantially that of the other roller.

6. In a method of repairing a sheet coating apparatus having a coating roller and an impression roller both rotatable at the same peripheral speed, the impression roller having a cylindrical peripheral shell that is harder than the part of the roller radially inwardly of the shell, and scraper means in pressure engagement with the periphery of the impression roller and which causes roughening and irregular wear of said periphery; the steps comprising machining the periphery of the impression roller to reduce the diameter thereof an amount no greater than the thickness of the hardened shell, and thereafter changing the speed of rotation of the one roller an amount sufficient to render the peripheral speed thereof substantially that of the other roller.

7. In a sheet coating apparatus, a coating roller, an impression roller means for mounting said impression roller in a manner so that it is removable from the remainder of the apparatus and is parallel to the coating 6 roller, driving means for rotating said rollers at the same peripheral speed to grip and feed sheet material therebetween to apply a coating of material from the coating roller to one side of the sheet material, scraper means in pressure engagement with the periphery of the impression roller for removing therefrom coating material that may become deposited thereon and with the scraper being such as to cause irregular wear of said periphery after which the impression roller may be removed from the apparatus and diametrally reduced and then replaced in the apparatus, means for positioning the axis of rotation of the diametrally reduced impression roller and that of the coating roller closer to one another, and variable speed transmission means forming part of said driving means for changing the speed of rotation of one roller relative to the other roller suflicient to render the peripheral speed of the two rollers substantially the same.

8. In a method of repairing a sheet coating apparatus having a coating roller, a removable impression roller parallel thereto, driving means including variable speed transmission means for rotating said rollers at the same peripheral speed to grip and feed sheet material therebetween to apply a coating of material from the coating roller to one side of the sheet material, scraper means in pressure engagement with the periphery of the impression roller for removing therefrom coating material that may become deposited thereon and with the scraper being such as to cause irregular wear of said periphery, the steps comprising removing the impression roller from the remainder of the apparatus, reducing its diameter, replacing it in the apparatus, positioning the axis of rotation of the diametrally reduced impression roller and that of the coating roller closer to one another than they were before removal of the impression roller, and changing the speed of rotation of one roller relative to the other by adjusting the variable speed transmission so as to render the peripheral speeds of the two rollers substantially the same.

9. In a sheet cating apparatus, a coating roller having means for applying a coating of material to one side of a sheet in a predetermined pattern over discontinuous areas that leaves uncoated regions adjacent to the coated areas, an impression roller, means for mounting said impression roller in a manner that it is removable from the remainder of the apparatus and is parallel to the coating roller, driving means for rotating the rollers at the same peripheral speed, a feed table, means for advancing the sheet along the feed table to the rollers in timed relation to the rotation of the rollers, the peripheries of said rollers cooperating to grip the sheet and feed the sheet therebetween and apply the coating to the sheet in said predetermined pattern, scraper means in pressure engagement against the periphery of the impression cylinder for removing therefrom coating material that has been deposited thereon by the coating roller and thereby prevent coating material from being deposited by the impression roller onto the other side of the sheet, the scraper means applying sufficient pressure to the surface of the impression roller to cause irregular wear of said periphery after which the impression roller may be removed from the apparatus and diametrically reduced and then replaced in the apparatus, means for repositioning the axis of rotation of the diametrally reduced impression roller and that of the coating roller closer together, and transmission means forming part of said driving means for adjusting in a continuously variable manner the speed of rotation of one roller relative to the speed of rotation of the other roller so that the undersized impression roller may be used with the coating roller and be rotated at substantially the same peripheral speed as thta of the coating roller.

(References on folllowing page) References Cited by the Examiner UNITED STATES PATENTS Wagner et a1. 226153 X Mackenzie 118241 Goyot 822.5 X Hayes 118212 Stafford et a1 101216 Shields 101216 Boehm 29-401 Showalter 118212 Nelson 29148.4

Williams 74221 Luenberger 74230.17 Steuet 74230.17

Lakin 29148.4

JOHN F. CAMPBELL, Primary Examiner.

THOMAS H. EAGER, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,268,982 August 30, 1966 Edward J. Schutze It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the heading to the printed specification, line 4, for

"Edward J, Schultze" read Edward J. Schutze column 5, line 73, after "roller" insert a comma; column 6, line 40, for "cating" read coating line 72, for "'thta" read that Signed and sealed this 1st day of August 1967.

(SEAL) Attest:

Edward M. Fletcher, Jr. EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

4. IN A METHOD OF REPAIRING A SHEET COATING APPARATUS HAVING A COATING ROLLER, AN IMPRESSION ROLLER ROTATABLE AT THE SAME PERIPHERAL SPEED AS AND COOPERATING WITH THE COATING ROLLER TO GRIP AND FEED A SHEET THEREBETWEEN TO APPLY A COATING OF MATERIAL FROM THE COATING ROLLER TO ONE SIDE OF THE SHEET, AND SCRAPER MEANS IN PRESSURE ENGAGEMENT WITH THE PERIPHERAL OF THE IMPRESSION ROLLER FOR REMOVING THEREFROM COATING MATERIAL THAT MAY BECOME DEPOSITED THEREON AND WHEREIN THE SCRAPER CAUSES IRREGULAR WEAR OF SAID PERIPHERY; THE STEPS COMPRISING MACHINING THE PERIPHERY OF THE IMPRESSION ROLLER TO REDUCE THE DIAMETER THEREOF, AND THEREAFTER CHANGING THE SPEED OF ROTATION OF THE ONE OF THE ROLLERS RELATIVE TO THAT OF THE OTHER ROLLER SUFFICIENT TO RENDER THE PERIPHERAL SPEED OF THE IMPRESSION ROLLER SUBSTANTIALLY THE SAME AS THAT OF THE COATING ROLLER. 